1. Field of the Invention
The present invention relates to a density modulate catheter for use in a high-quality representation of a volume, wherein the real-time movement of the catheter is determined using a lower-quality representation of a portion of the volume.
2. Background of the Invention
3-D angiography is a relatively new application of an X-ray interventional procedure that utilizes a rotational run of an X-ray apparatus to acquire a series of 2-D X-ray projections along a circular (or almost circular) orbit. The rotational run is acquired by moving an X-ray source and an Image Intensifier (II camera mounted on a rotatable C-arm about a patient, while a continuous injection of contrast bolus is administered into the vasculature of the patient. The rotational series of 2-D image data is then sent to a cone beam reconstruction process, which generates a 3-D reconstruction of the patient""s vascular structure.
The vascular structures depicted in the 3-D reconstructed images are then studied by the clinicians in order to plan an interventional procedure (operation). Once the plan is determined, catheters are used to carry out what is called an endovascular procedure. The entire procedure is constantly monitored by the clinicians under the guidance of a 2-D fluoroscopic imaging procedure. The 2-D fluoroscopic imaging procedure uses the same imaging apparatus and patient positioning as was used to perform the 3-D angiography procedure. Before starting the intervention, the clinician studies the previously acquired 3-D vasculature structures in order to choose an optimum way to place the C-arm to generate the best 2-D fluoroscopic image, thereby maximizing the ability of the 2-D procedure to aid in guiding the catheters during the operation.
Accordingly, the X-ray fluoroscopic image is used as a navigation tool by the clinicians to aid maneuvering the catheters through tortuous paths of the patient""s vasculature. Every once-in-a-while the clinicians must inject contrast material to opacity the vessel, so that the vessel can be seen under the 2-D fluoroscopic imaging procedure. It is also common current practice to capture and store a contrast-enhanced fluoroscopic image, and then subtract that image from subsequent images. This results in a static display of the vascular structures (displayed in white), while the live (real-time) catheter appears in black This procedure is known as xe2x80x9croad mappingxe2x80x9d. The roadmap is a 2-D projection of the vascular structures, and like any 2-D projection of a 3-D body has substantial positional ambiguity.
It is an object of the present invention to provide a more accurate real-time representation of the movement of an object in a volume when a previously acquired high-quality static representation of the volume is available but only a lower-quality real-time representation is available for detecting movement of the object. In this regard, it is an object of the present invention to develop a real-time high-quality 3-D representation of the movement of a catheter in the brain of a patient.
It is a further object of the present invention to present the real-time movement of the catheter in three dimensions to a doctor performing a neurosurgical procedure.
An even further aspect of the invention is the design of a new catheter for facilitating detection of the catheter.
In this regard, once coordinate transformations are determined, a novel interactive real-time image visualization is provided which merges the stored 3-D representations of the volume with a real-time 3-D reconstruction of the detected movement of the object.
Described is an intensity modulated device for use and easy detection in fluoroscopy based 3-D neural navigation. The inventive device comprises a catheter containing an X-ray opaque material deposited on its outside surface along its length. The X-ray material has an X-ray absorption coefficient that varies along the length of the catheter. As a result, when one X-ray image is subtracted from another X-ray image, high intensity changes with respect to the catheter appear in a subtracted image.